Im new to painting and have only sprayed a few vehicles. all of which were outside and turned out great.

Some of the guys have suggested really good advice previously. the tape was a on point. use 3M and masking paper! thin paper bleeds, some tape is way too sticky... messes up custom paint work and is hard to clean off a "tape off and spray" basis.

if your using the same color over the old paint I dont see why you would need primer. I wouldnt even prime it myself , would just sand (320?) down into the color past the clear, spray it ,then clear it. It is probably recomended you use a sealer or adhesion promoter type primer. Im saying I would just spray it
if you ever hit metal use an etcher primer.
I have also bought paint from Napa for the last two vehicles. this turned out to be pretty good paint. easily accessible also.